Issue #2889438 by chr.fritsch, seanB, marcoscano, Wim Leers, rogerpfaff, phenaproxima, larowlan: Delete media delivered icons on uninstall

core/modules/media/media.install

@@ -17,7 +17,15 @@ function media_install() {
 
   $files = file_scan_directory($source, '/.*\.(svg|png|jpg|jpeg|gif)$/');
   foreach ($files as $file) {
-    file_unmanaged_copy($file->uri, $destination, FILE_EXISTS_ERROR);
+    // When reinstalling the media module we don't want to copy the icons when
+    // they already exist. The icons could be replaced (by a contrib module or
+    // manually), so we don't want to replace the existing files. Removing the
+    // files when we uninstall could also be a problem if the files are
+    // referenced somewhere else. Since showing an error that it was not
+    // possible to copy the files is also confusing, we silently do nothing.
+    if (!file_exists($destination . DIRECTORY_SEPARATOR . $file->filename)) {
+      file_unmanaged_copy($file->uri, $destination, FILE_EXISTS_ERROR);
+    }
   }
 
   // Grant the "view media" permission to all users by default.

core/modules/media/tests/src/Functional/MediaInstallTest.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace Drupal\Tests\media\Functional;
+
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Tests media Install / Uninstall logic.
+ *
+ * @group media
+ */
+class MediaInstallTest extends BrowserTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['media'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+    $this->drupalLogin($this->drupalCreateUser(['administer modules']));
+  }
+
+  /**
+   * Tests reinstalling after being uninstalled.
+   */
+  public function testReinstallAfterUninstall() {
+    $page = $this->getSession()->getPage();
+    $this->container->get('module_installer')->uninstall(['media'], FALSE);
+    $this->drupalGet('/admin/modules');
+    $page->checkField('modules[media][enable]');
+    $page->pressButton('Install');
+    // @todo Remove this if-statement in https://www.drupal.org/node/2895059
+    if ($page->find('css', 'h1')->getText() == 'Are you sure you wish to enable experimental modules?') {
+      $page->pressButton('Continue');
+    }
+    $this->assertSession()->pageTextNotContains('could not be moved/copied because a file by that name already exists in the destination directory');
+  }
+
+}